Stylopoma multiavicularia, Rodrigues & Almeida & Vieira, 2020

Rodrigues, Maria J. S., Almeida, Ana C. S. & Vieira, Leandro M., 2020, New species of Stylopoma (Bryozoa, Cheilostomata) from Bahia State northeastern Brazil, Zootaxa 4786 (4), pp. 516-534 : 522-524

Stylopoma multiavicularia n. sp.

( Fig. 4 A–D; Tables 1, 2)

urn:lsid:zoobank.org:act:7FD86B49-2ADB-4852-A149-E55C3A473AF3

Material examined. Holotype: UFBA 1973.1 , Costa dos Coqueiros, Bahia State, Brazil, 12°47’ S; 38°06’ W, 26 m, coll. 2005 by LAMEB-UFBA . Paratypes: UFBA 2385.1 , Costa dos Coqueiros, Bahia State, Brazil, 12°44’ S; 38°05’ W, 23 m, coll. 2002 by LAMEB-UFBA; UFPE 134 , UFPE 142 , UFPE 156 , Costa dos Coqueiros, Bahia State, Brazil, 12°45’– 12°51’ S; 38°06’– 38°12’ W, 22–23 m, coll. 2007 by LAMEB-UFBA. Additional specimens: UFBA 350.1 , Costa do Descobrimento , Bahia State, Brazil, 16°07’ S; 38°29’ W, 35 m, coll. 1996 by REVIZEE Central ; UFBA 1425.2 , UFBA 1426.5 , UFBA 1430.1 , Banco de Abrolhos , Costa das Baleias, Bahia State, Brazil, 17°20’– 18°10’ S; 38°35’– 38°36’ W, 15–30 m, coll. by Zelinda Leão ; UFBA 1556.1 , UFBA 1557.1 , UFBA 1558.1 , UFBA 1559.1 , UFBA 1560.1 , UFBA 1561.1 , UFBA 1562.1 , Banco de Abrolhos , Costa das Baleias, Bahia State, Brazil, 18°20’– 19°17’ S; 38°42’– 39°06’ W, coll. by Ruy Kikuchi .

Diagnosis. Stylopoma with frontal wall with 40–62 pseudopores; primary orifice with a short U-shaped sinus

and moderate subrectangular condyles with smooth and unlipped margins; 2–5 adventitious avicularia with variable orientation, with long and acute rostrum (up to 0.156 mm long); ovicell bearing 3–6 adventitious avicularia and with semicircular opening.

Etymology. The species name ‘ multiavicularia ’ is from the Latin multi, many, and avicularia, in reference to the numerous frontal avicularia seen in older autozooids of this species.

Description. Colony encrusting, uni to multilaminar. Autozooids primarily regularly oriented, subhexagonal, to irregularly polygonal, limited by sutures, becoming irregularly oriented, their boundaries obscured with increasing calcification ( Fig. 4A, C ). Frontal wall with smooth calcification except around the orifice, sometimes with a pointed umbo with granular calcification; surface evenly perforated by 40–62 large frontal pseudopores placed in deep infundibular cavities, marginal pores slightly larger and more elongate than frontal ones. Primary orifice Dshaped ( Fig. 4B ), as wide as long, with smooth distal rim; proximal edge with a U-shaped median sinus about 1/4 of the orifice length; a pair of moderate proximolateral subrectangular condyles [0.009 –0.017 mm high (0.014 ± 0.030; n = 10)] with smooth surface and unlipped margins. Secondary orifice slightly elevated, with nodular calcification. Autozooid with 2–6 elongate adventitious avicularia ( Fig. 4C ), rostrum subtriangular with acute tip, complete crossbar and elliptical foramen; 2 avicularia distally or distomedially oriented and placed at each side of the orifice (rarely single), and 1–3 additional avicularia placed on the frontal wall, mainly at zooidal margins, with variable orientation ( Fig. 4 A–D). Vicarious avicularia not observed. Ovicells prominent ( Fig. 4D ), obscuring the orifice of the maternal zooid; ooecium globose, with pseudoporous and tubercular surface, bearing 3–6 adventitious avicularia; semicircular opening, with entire proximal labellum and a distinct suture, not visible in frontal view.

Remarks. Stylopoma multiavicularia n. sp. can be distinguished from all other congeners reported in Brazil by having long adventitious avicularia, that can reach up to 0.156 mm in length, whereas in the other species the maximum length is never more than 0.100 mm ( Winston et al. 2014; Ramalho et al. 2018).

Among Stylopoma worldwide, S. multiavicularia n. sp. mostly resembles S. corallinum n. sp., S. haywardi and Stylopoma horarium Tilbrook, 2006 by having single or paired latero-oral avicularia and frontal avicularia with variable orientation. Stylopoma multiavicularia n. sp., however, has autozooids subhexagonal or irregularly polygonal (subrectangular or subquadrangular in S. corallinum n. sp., S. haywardi and S. horarium ), primary orifice with U-shaped sinus (shallow and drop-shaped in S. corallinum n. sp., deep and drop-shaped in S. haywardi and S. horarium ), latero-oral avicularia distally oriented (laterally oriented in S. corallinum n. sp., S. haywardi and S. horarium ), and no vicarious avicularia (spatulate in S. corallinum n. sp., S. haywardi and S. horarium ) ( Tilbrook 2006; Winston & Woollacott 2009).

Distribution. Brazil: Bahia State. Stylopoma multiavicularia n. sp. occurs in Costa dos Coqueiros, Costa do Descobrimento and Costa das Baleias. This species is found associated to other bryozoans such as Celleporaria Lamouroux, 1821 , calcareous nodules and rocks, at 15–35 m depth.

Figures

FIGURE 4. Stylopoma multiavicularia n. sp., UFBA 1973.1, holotype. A. Group of young autozooids. B. Primary orifice and adventitious avicularia. C. Group of older autozooids. D. Group of ovicelled zooids. Scale bars: A, D. 400 µm; B. 200 µm; C. 500 µm.